Additives for lubricating compositions

ABSTRACT

THE INVENTION PROVIDES A NOVEL OIL-SOLUBLE COMPOUND, PARTICULARLY SUITABLE AS AN ADDITIVE FOR LUBRICATING COMPOSITIONS, SELECTED FROM THE GROUP CONSISTING   R1-CO-NH-(A)-(B)N AND R1-CO-O-NH3(+)-(A)-(B)N   WHEREIN R1 IS SELECTED FROM THE GROUP CONSISTING OF ALKYL AND ALKENYL RADICALS CONTAINING AT LEAST 12 CARBON ATOMS; A IS AN AMINO HYDROCARBON OR AMINO HYDROXY HYDROCARBON RADICAL CONTAINING FROM 1 TO 6 AMINO GROUPS; N OF -(B)N IS AN INTEGER OF FROM 1 TO 6, B IS A RADICAL HAVING THE FORMULA -(CRR)M-SO3H WHERE M IS 3 OR 4, SAID RADICAL BEING ATTACHED THROUGH THE CARBON ATOM TO A NITROGEN ATOM OF A, AND WHEREIN R IS SELECTED FROM THE GROUP CONSISTING OF A HYDROGEN ATOM AND A HYDROCARBON GROUP HAVING NOT MORE THAN 10 CARBON ATOMS, PROVIDED HOWEVER THAT ANY TWO SUBSTITUENTS OF R ON ADJOINING CARBON ATOMS MAY TOGETHER FORM A CYCLIC SYSTEM, AND THE INTERNAL SALTS OF THE FOREGOING COMPOUNDS.

United States Patent U.S. Cl. 260-401 3 Claims ABSTRACT OF THE DISCLOSURE The invention provides a novel oil-soluble compound, particularly suitable as an additive for lubricating compositions, selected from the group consisting wherein R is selected from the group consisting of alkyl and alkenyl radicals containing at least 12 carbon atoms; A is an amino hydrocarbon or amino hydroxy hydrocarbon radical containing from 1 to 6 amino groups; n of (l3) is an integer of from 1 to 6, B is a radical having the formula -(CRR) -SO H where m is 3 or 4, said radical being attached through the carbon atom to a nitrogen atom of A, and wherein R is selected from the group consisting of a hydrogen atom and a hydrocarbon group having not more than 10 carbon atoms, provided however that any two substituents of R on adjoining carbon atoms may together form a cyclic system, and the internal salts of the foregoing compounds.

This application is a divisional application divided out of our copending application Ser. No. 519,008 filed Ian. 7, 1966, now Pat. No. 3,367,864 issued Feb. 6, 1968.

The invention relates to additives for lubricating compositions. In particular, the additives with which this invention is concerned are detergents which are effective cold sludge dispersants.

In the lubrication of modern internal combustion engines deposits may be formed in the engines in two ways and there are two distinct problems involved in keeping the engines clean. One problem is the deposition of soot, lacquers and other deposits, mainly in the piston ring zone, under high speed, and consequently high temperature, operating conditions. These deposits may arise from partial combustion products of the fuel or as the result of the oxidation or thermal degradation of the lubricant or both. This problem is alleviated by the addition to the lubricating oil of what are known in the art as high temperature detergents, conventional detergents or normal detergents. The other problem is the deposition of another kind of dirt. This dirt has become known as cold sludge. Cold sludge is formed in cold weather and under driving conditions obtaining in cities and in other conditions when the engines never truly warm up. This latter problem is alleviated by the addition to the lubricant of additives known as cold sludge dispersents. Cold sludge is derived almost entirely from the fuel and is normally wet.

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In the past the conventional detergents have in general been metal containing derivatives of organic compounds such as basic alkaline earth metal petroleum or alkyl benzene sulphonates, basic alkaline earth metal salts of phosphosulphurised polybutenes or alkaline earth metal phenates. The cold sludge dispersants, on the other hand, have in general been copolymers of polar monomers such as N-vinyl pyrrolidone with oil-solubilising copolymerisable monomers such as long-chain alkyl methacrylates.

More recently, products having useful detergent and cold sludge dispersant properties have been obtained by reacting a long chain monoalkenyl succinic anhydride, preferably polyisobutenyl succinic anhydride, with polyamines such as polyethylene polyamines or fi-aminoethyl piperazine.

According to the present invention there is provided a novel oil-soluble compound, particularly suitable as an additive for lubricating compositions, selected from the group consisting Ri-C wherein R is selected from the group consisting of alkyl and alkenyl radicals containing at least 12 carbon atoms; A is an amino hydrocarbon or amino hydroxy hydrocarbon radical containing from 1 to 6 amino groups; n of (B) is an integer of from 1 to 6, B is a radical having the formula (CRR) SO H where m is 3 or 4, said radical being attached through the carbon atom to a nitrogen atom of A, and wherein R is selected from the group consisting of a hydrogen atom and a hydrocarbon group having not more than 10 carbon atoms, provided however that any two substituents of R on adjoining carbon atoms may together form a cyclic system, and the internal salts of the foregoing compounds.

One example of a novel compound according to the invention is a sulphonic acid or a salt thereof or a sulpho betaine which is obtainable by reacting a long chain mono alkenyl carboxylic acid or anhydride with a di or polyamino compound containing at least one primary amino group, the reaction product being reacted with a sultone of the general formula:

wherein each R may be a hydrogen atom, an alkyl or substituted alkyl radical, a phenyl or substituted phenyl radical, or any two of the substituents R on adjoining carbon atoms may be taken together to form a cycl system. A preferred sultone is propane sultone.

In another form of the present invention there is provided a sulphonic acid or a salt thereof or a sulphobetaine which is the reaction product of a sultone with a longchain saturated or unsaturated alkyl amide containing at least one basic nitrogen atom.

Preferably the long-chain alkyl radical is derived from a normally liquid oil-soluble polyolefin having a molecular weight of 7003000, e.g. 750 to 1500, although in certain instances it may be possible to employ shorter alkyl chains having not less than 12 carbon atoms. 'Preferably the polyolefin is polyisobutylene.

The novel compounds of the present invention may be prepared by reacting a sultone with a compound containing a long saturated or unsaturated alkyl chain linked through an amide grouping to a grouping having at least one basic nitrogen atom. The reaction goes readily, and may be effected by mixing equimolar proportions of the reactants, optionally in a solvent, and maintaining the mixture at a temperature of from C. to 200 C. The temperature is not critical, and may be chosen so that the reaction mixture has a convenient viscosity for being stirred.

A preferred method for preparing some of the novel compounds of the invention comprises heating together a long chain alkenyl carboxylic acid or anhydride with a dior polyamino compound containing at least one primary amino group with elimination of water and subsequently reacting the product thus formed with a sultone as hereinbefore defined to form a compound which contains a sulphonic acid or sulphobetaine grouping.

An alternative method of preparing these novel compounds comprises reacting together a mixture of a suitable dior polyamino compound containing at least two primary amino groups and a sultone as herein described to yield an amino sulphonic acid or sulphobetaine containing at least one primary amino group. The reaction product is subsequently heated with an acidic reagent containing a long saturated or unsaturated alkyl chain.

The long chain mono alkenyl carboxylic acid employed in the foregoing methods may be prepared by condensing a polyolefin with an a,,8 unsaturated monocarboxylic acid containing from 3 to 8 carbon atoms. The po'lyolefin may be, for example, a halogenated polyisobutylene.

Suitable dior polyamino compounds for use in the present invention are alkylene polyamines having the general formula:

wherein x is an integer and R; is a divalent alkylene radical. Examples of such amines are ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine and mixed higher polyethylene polyarnines. Other alkylene polyamines such as di(1,2-propylene) triarnine, or N-(Z-amino ethyl) trimethylene diamine may be employed, if desired. Such alkylene polyamines may be first reacted with a m-lactone, preferably oc-blltYlO lactone, as described in British patent specification No. 1,054,370 or with dicyandiamide as described in our co-pending application No. 470,564 provided that such reaction products contain at least one primary amino group.

Useful higher polyamines have molecularweights from 300 to 1000 or 5,000, preferably 400 to 600 especially those prepared by polymerising ethylene imine. The process of polymerising ethylene imine gives rise to mixtures of polyethylene polyamines having a wide range of molecular weights. These may be divided into mixtures having narrow ranges of molecular weights, those indicated being the most useful in this invention.

Another polyamine which is useful in this invention is one marketed by Union Carbide Corporation under the name of Polyamine D (PAD) which is stated to be predominantly a mixture of isomeric pentaethylene hexamines of formula C H N and related hexamines containing piperazine rings and 12 C atoms. The average molecular weight of the mixture is approximately that of pentaethylene hexamine, i.e. 233, and the mixture contains a predominance of amines having 24 primary amino groups and at least two secondary amino groups.

Other suitable diamino compounds which may be employed are N-dialkylamino alkylamines of the general formula:

wherein R is a divalent alkylene radical and R and R are alkyl radicals. Examples of such N-dialkylamino alkylamines include dimethylaminomethylamine, dimethylaminoethylamine, dimethylaminopropylamine, dimethylaminobutylamine, dimethylaminoheptylamine, diethylaminomethylamine, diethylaminopropylamine, diethylaminoamylamine, dipropylaminopropylamine, methylpropylaminoamylamine and propylbutylaminoethylamine.

Further suitable diamino compounds are N-(B-aminoalkyl) piperazines of formula:

wherein R is an alkylene radical containing 1 to 3 carbon atoms and R is a hydrogen atom or a hydrocarbon radical containing from 1 to 3 carbon atoms.

Aromatic dior polyamines may also be used in the invention such as, for example, p-phenylene diamines, O-phenylene diamine, benzidine and substituted derivatives thereof.

Other miscellaneous dior polyamino compounds which may be used in the invention are N-(Z-aminoethyl) ethanolamine and hydroxy tetraethylene tetramine,

Specific examples of sultones which may be used in the present invention include the following, the nomenclature being as indicated in the general formulae:

propane sultone 2,2 dimethyl propane sultone 1,4 butane sultone 3 methyl propane sultone 3,3 dimethyl propane sultone 1,1,3 trimethyl propane sultone 2,2,3,3 tetramethyl propane sultone 1,2,3,3 tetramethyl propane sultone 1,2,2,3,3 pentamethylpropane sultone 2,3,3 trimethyl-Z-phenyl propane sultone 2,2,4,4 tetramethyl butane sultone hydroxy propane sultone Octadecane sultone Examples of sultones in which in the above general formula two radicals R are taken together to form a cyclic system, are those having the structures so on I or naphtho-l, 8 sultone.

For further details, reference is made to J.A.C.S., 86, page 4641, Nov. 5, 1964, where an article by Chline, Allred and Bordwell is entitled Structures of Sultones from Proton Magnetic Resonance.

Whilst the additives of the present invention are valuable ashless dispersants it may be desirable, in certain cirmumstances, particularly for use in diesel engines, to include a minor proportion, for example, up to 10% by weight of an alkaline earth metal base, erg. calcium carbonate. This may be incorporated by any of the wellknown methods, as illustrated in the' examples which follow.

Suitable basic compounds which maybe reacted with the novel sulphonic acids of the present invention are the alkaline earth metal oxides or hydroxides,

This invention also includes the novel compounds dissolved in a lubricating oil in an amount of from 0.5 to 5.0% by weight on the weight of the lubricating oil.

It is to be understood that the lubricating compositions prepared by dissolving the novel compounds of the present invention in a lubricating oil may also contain copper deactivators, pour-point depressants, antioxidants, vis cosity index improvers and other conventional additives as necessary.

Particularly preferred antioxidants which may be used in conjunction with the additives of the present invention are the metal salts of dialkyl or dialkyaryl dithiophosphates, especially the zinc salts of dialkyl dithiophosphoric acids derived from C -C alcohols. The dithiophosphate may be present in the composition in amounts from 0.2 to 2% and preferably from 0.5 to 1.5% by weight based on the weight of the composition.

Following is a description by way of example of a method of preparing a typical additive in accordance :with the present invention.

EXAMPLE where 0 RiC is a long chain monocarboxylic acid residue derived from the condensation of a halogenated polyisobutylene with a C C il-unsaturated monocarboxylic acid; R is a x is an integer of from 1 to 6; B is a divalent alkylene radical having from 2 to 5 carbon atoms;

radical derived from propane sultone; and n is an integer of from 1 to 6.

2. A compound as claimed in claim 1 wherein said halogenated polyisobutylene is derived from a polyisobutylene having a molecular weight of from 700 to 3000.

3. A novel oil-soluble compound, particularly suitable as an additive for lubricating compositions, having the formula:

References Cited UNITED STATES PATENTS 2,993,918 7/1961 Mannheimer 260-401 3,198,822 10/1961 Mannheimer 260-458 3,187,026 6/ 1965 Klass 260-401 ELBE'RT L. ROBERTS, Primary Examiner US. Cl. X.R. 

